(4bd) Environmental Perspectives On the Interactions of Nanomaterials and Microorganisms

The number of nanomaterials in commercial production is rapidly rising. Much of this production is for new generations of nanomaterial enhanced consumer products. As a result of escalating production, release of engineered nanomaterials to the environment will increase significantly. In some cases, release may be intentional as when reactive iron nanoparticles are deployed for environmental remediation. In most cases release will be unintentional, as when nanoparticles are leached from consumer products into wastewater and concentrate in sludges that are ultimately applied as fertilizer to agricultural fields. Microorganisms will normally be the first organisms to interact with engineered nanomaterials in the environment, but interactions between microorganisms and engineered nanomaterials are poorly understood. This poster summarizes work that demonstrates both the impact of nanomaterials on microbial communities and the impact of bacteria on nanomaterials themselves. For example, nanomaterials currently being designed for in situ remediation of groundwater contamination by chlorinated organic compounds are added at high concentrations directly into aquifers. Microcosm studies carried out with contaminated aquifer materials show that these can dramatically change the composition of microbial communities, despite not showing broad biocidal effects. Investigations are currently underway to develop strategies to combine nanoparticle-based remediation treatments with dechlorinating microorganisms to achieve synergism and more rapid contaminant degradation. This poster also presents the results of an investigation that demonstrates the ability of bacteria to directly degrade polymeric coatings on nanoparticles. The implications of such microbial processing on the environmental fate, partitioning and potential ecotoxicity of engineered nanoparticles will be discussed.